Title

Author

Date of Degree

Document Type

Dissertation

Degree Name

Ph.D.

Program

Biology

Advisor(s)

Diego Loayza

Subject Categories

Biology | Cell Biology | Molecular Biology

Keywords

POLA2, Polymerase alpha, Shelterin, Telomeres

Abstract

Telomeres consist of TTAGGG repeats, which end with a 3' G-overhang and are bound by a six-protein complex, known as Shelterin. In humans, telomeres shorten at each cell division, unless telomerase is expressed and able to add telomeric repeats to the 3' G-overhang. However, for effective telomere maintenance, the DNA strand complementary to that made by telomerase must be synthesized. In this study, I focused on the Polα/primase complex, in particular the subunits p68 (POLA2, the regulatory subunit) and p180 (Polα, the catalytic subunit), and their potential roles at telomeres. I was able to detect p180, p68 and OBFC1, a subunit in the CST complex, at telomeres in S phase using chromatin immunoprecipitations. I could also show that OBFC1, Shelterin and Polα/primase interact, revealing contacts occurring at telomeres. Finally, depletion of p68 by shRNA and p68 and p180 by siRNA, led to increased overhang amounts at telomeres. I propose a model in which Polα-primase is important for proper telomeric overhang processing, perhaps through fill-in synthesis. These results shed light on important events necessary for efficient telomere maintenance and protection.

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